HHS Public Access Author manuscript Author Manuscript
J Infus Nurs. Author manuscript; available in PMC 2017 October 26. Published in final edited form as: J Infus Nurs. 2016 ; 39(5): 281–286. doi:10.1097/NAN.0000000000000186.
Thyroid Emergencies Angela M Leung, MD, MSc Division of Endocrinology, David Geffen School of Medicine at UCLA, and the VA Greater Los Angeles Healthcare System, Los Angeles, California.
Abstract Author Manuscript
Myxedema coma and thyroid storm are thyroid emergencies associated with increased mortality. Prompt recognition of these states—which represent the severe, life-threatening conditions of extremely reduced or elevated circulating thyroid hormone concentrations, respectively—is necessary to initiate treatment. Management of myxedema coma and thyroid storm requires both medical and supportive therapies and should be treated in an intensive care unit setting.
Keywords hypothyroidism; hyperthyroidism; ICU; myxedema coma; thyroid emergencies; thyroid storm
Author Manuscript
The thyroid is a 15- to 20-gram gland located in the anterior neck. It is responsible for the production of the thyroid hormones T4 (thyroxine) and T3 (triiodothyronine). Various factors can affect thyroid hormone synthesis, including acute illness, coexisting morbidities, and certain medications. Both the states of low thyroid hormone concentrations (hypothyroidism) and thyroid hormone excess thyrotoxicosis) can be transient or permanent. The decompensated, severe forms of hypothyroidism and hyperthyroidism, termed myxedema coma and thyroid storm, are associated with increased morbidity and mortality. Prompt recognition of both conditions is necessary to initiate treatment and supportive measures. This review will summarize the essential principles of the clinical manifestations, diagnostic methods, and treatments of hypothyroidism and hyperthyroidism, both in the nonacute and life-threatening forms of these diseases.
THYROID HORMONE PRODUCTION AND METABOLISM Author Manuscript
The normal physiology of the hypothalamic-pituitary-thyroid axis involves the production of T4 and T3 by the thyroid gland, a process that is regulated by thyroid-stimulating hormone (TSH) secreted by the pituitary, which is, in turn, regulated by thyrotropin-releasing hormone (TRH) secreted by the hypothalamus. Both serum T4 and T3 concentrations act as negative feedback regulators of TSH and TRH secretion, but can be altered by
Corresponding Author: Angela M. Leung, MD, MSc, VA Greater Los Angeles Healthcare Sysem, Divison of Endocrinology (111D), 11301 Wilshire Blvd, Los Angeles, CA 90073 ([email protected]). Angela M. Leung, MD, MSc, is an assistant clinical professor of medicine in the Division of Endocrinology at the David Geffen School of Medicine at the University of California, Los Angeles, and the VA Greater Los Angeles Healthcare System, both in Los Angeles, California. The author has no other potential conflicts of interest to disclose.
Leung
Page 2
Author Manuscript
environmental conditions—including food availability and temperature—and disease states, such as infection.1 Thyroid hormone synthesis is achieved first through active transport of circulating iodide, which is taken in from the diet, by the sodium/iodide symporter located at the basolateral membrane of the thyroid follicular cell.2 Iodide then becomes oxidized by thyroid peroxidase (TPO) and hydrogen peroxide at the apical membrane, which then attaches to the tyrosyl residues on thyroglobulin (Tg) to produce monoiodotyrosine (MIT) and diiodotyrosine (DIT). MIT and DIT are the precursors to the thyroid hormones, which are produced by the linkage of 2 DIT molecules to form T4 and the linkage of MIT and DIT to produce T3. Release of T4 and T3 into the circulation results from the digestion of Tg in MIT and DIT by endosomal and lysosomal proteases.
Author Manuscript
The metabolic effects of thyroid hormone action result from the binding of the thyroid hormone to thyroid hormone transporters located in specific target tissues, which is mediated by the thyroid hormone nuclear receptor (TR) that is encoded by the genes TRα and TRβ.3 While the sole source of T4 is the thyroid gland, the majority (approximately 80%) of T3 is produced from the extrathyroidal conversion of T4 to T3 by the action of the 5 ´-deiodinase enzymes—D1 or D2—located in the liver, brain, brown adipose tissue, and muscles.4 T4 can also be converted to the inactive thyroid hormones, reverse T3 or T2, by the 5´-deiodinase D3. The activity and expression of the deiodinases are specific to different tissues and environmental conditions.
SERUM THYROID FUNCTION AND ANTIBODIES Author Manuscript
Serum TSH is the most sensitive test to suggest thyroid dysfunction, because of the logarithmic-linear relationship between serum TSH and thyroid hormone levels. Overt thyroid dysfunction, whether referring to hypothyroidism or hyperthyroidism, is defined by the sole abnormality of an elevated serum TSH concentration, while subclinical thyroid dysfunction refers to both elevated serum TSH and decreased T3 and/or T4 concentrations. The range of subclinical to overt thyroid dysfunction can be regarded as a continuum of increasingly severe biochemical thyroid disease, which incidentally may or may not correlate to the severity of any corresponding symptoms, if present.
HYPOTHYROIDISM
Author Manuscript
Hypothyroidism refers to the state of low circulating thyroid hormones. In 2 large US population-based studies of data collected in the 1980s to the 1990s, the prevalence of overt hypothyroidism ranged from 0.3% to 0.4%, while that of subclinical hypothyroidism ranged from 4.3% to 8.5%, among the general population.5, 6 The most common etiology of hypothyroidism in the United States is Hashimoto’s thyroiditis, an autoimmune disease that is more prevalent among older women; nutritional iodine deficiency is the most common etiology worldwide. Additional etiologies of hypothyroidism include a history of thyroidectomy, radioactive iodine therapy, and, less commonly, decreased TSH production by the pituitary. Predisposition factors for the development of hypothyroidism include thyroid autoimmunity (which can be assessed by the determination of serum thyroid
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 3
Author Manuscript
autoantibodies, such as TPO and [Tg] antibody titers), the use of certain medications (ie, lithium, amiodarone, interferon-alpha), and excess iodine exposure (ie, from iodinated contrast radiographic studies), in which individuals with a history of thyroid disease are at higher risk of iodine-induced hypothyroidism.7 Thyroid hormone is important for the metabolic functions of many major organs, including the heart, brain, liver, and muscle. Signs and symptoms of hypothyroidism are widely variable (Table 1), often subtle, and may include fatigue, malaise, weight gain, dry and puffy skin, constipation, cold intolerance, altered cognition, and hyporeflexia. In children, there may be stunted growth, and in women, menstrual abnormalities may be present. Hypothyroidism Among Women of Reproductive Age and in Children
Author Manuscript
Normal thyroid function is particularly important among pregnant and lactating women, the developing fetus, and young children. As thyroid hormone is crucial for the complex processes of neurodevelopment and growth,8 which begins in the first trimester of pregnancy and continues into the first few years of infancy, these groups are especially susceptible to the effects of even mild thyroid dysfunction. Several studies have demonstrated that low thyroid hormone levels among pregnant women are associated with increased risks of preterm delivery, spontaneous miscarriage, fetal death, and cognitive deficits,9 including a decrement in intelligence quotient and memory scores of the offspring, compared with euthyroid women.10–13 Neuroimaging studies also show abnormalities of hippocampal and corpus callosum size, and of gray matter, among children with a form of low thyroid hormone levels at birth termed congenital hypothyroidism.14, 15 Myxedema Coma
Author Manuscript
Myxedema coma refers to the state of severe, life-threatening, and decompensated hypothyroidism in which thyroid hormone levels are dangerously low. The diagnosis appears to be more common in elderly women with long-standing preexisting hypothyroidism. Triggers may include cold temperature (thus, it is more common during winter months); precipitating comorbidities, such as infection, stroke, and heart failure; or the use of sedative, analgesic, antidepressant, hypnotic, antipsychotic, or anesthetic medications.16 Patients with preexisting hypothyroidism may also present with myxedema coma following a period of prolonged noncompliance with thyroid hormone replacement.
Author Manuscript
Signs and symptoms usually are exacerbations of the usual manifestations of hypothyroidism and may include extreme lethargy, which can progress to stupor or coma, hypothermia, respiratory depression, bradycardia, hyponatremia, and renal impairment. The diagnosis of myxedema coma is made with the confirmation of a biochemical thyroid profile consistent with hypothyroidism and corresponding clinical manifestations. A diagnostic scoring system has been proposed to guide the clinician toward a diagnosis of myxedema coma based on body temperature, central nervous system signs, gastrointestinal symptoms, precipitating events, cardiovascular dysfunction, and metabolic disturbances.17 Treatment of myxedema coma should be considered as quickly as possible, given the increased mortality of the disease (25%–60% despite treatment),18 and can be started even before confirmation of laboratory results demonstrating abnormal serum TSH and T4 J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 4
Author Manuscript
concentrations. The management of myxedema coma should be in an intensive care unit (ICU) setting. The central tenets of treatment are thyroid hormone replacement, stress-dose corticosteroids if concomitant adrenal insufficiency is suspected, supportive care, and the treatment of any underlying and coexisting conditions (Table 2). Supportive care may include the administration of intravenous (IV) fluids, sodium replacement if hyponatremia is present, and the use of warming blankets (although aggressive rewarming should be avoided, given the risks of vasodilation).19
Author Manuscript
Thyroid hormone replacement should be administered as T4 and/or T3, often intravenously, given the impaired state of the patient. Suggested regimens for the initial and maintenance doses of thyroid hormone in a patient with myxedema coma are provided in Table 2. In general, a loading dose of 200 to 400 µg IV levothyroxine (T4) is to be followed by a maintenance dose of 1.6 µg/kg/d when given orally or 75% of this when given intravenously; consideration can also be made for the coadministration of liothyronine (T3), since T4 to T3 conversion may be impaired in patients with myxedema coma.20 It is important to note that IV thyroid hormone replacement should be administered only as a push through a syringe, rather than through infusion tubing, in which up to 40% of the starting concentration may be lost from adherence to polypropylene tubing.21 Improvements in serum T3 and T4 concentrations may be seen before the normalization of serum TSH concentrations, and measurement of serum thyroid function tests every 1 to 2 days during treatment is reasonable.20 Improvements in clinical cardiovascular, renal, pulmonary, and metabolic parameters may take as much as a week to be observed.20
THYROTOXICOSIS Author Manuscript
Thyrotoxicosis refers to the state of thyroid hormone excess arising from either overproduction from the thyroid gland (termed hyperthyroidism) or extrathyroidal, including exogenous, sources. Of the etiologies attributable to hyperthyroidism, the most common cause worldwide is Graves’ disease, resulting from the autoimmune stimulation of the thyroid by serum thyroid-stimulating immunoglobulin, followed by toxic multinodular goiter and toxic adenoma. In the United States, the prevalence of hyperthyroidism from all causes is approximately 1.2%, of which 0.5% is overt and 0.7% is subclinical.22 Other causes of thyrotoxicosis include overproduction of TSH from a pituitary adenoma, thyroiditis, exogenous thyroid hormone ingestion, ectopic hyperthyroidism (such as from struma ovarii or metastatic thyroid cancer), or human chorionic gonadotropin-mediated hyperthyroidism (such as from hyperemesis gravidarum or a molar pregnancy).
Author Manuscript
The signs and symptoms of thyrotoxicosis are reflective of the excess concentrations of thyroid hormone present (Table 3) and can include anxiety, fatigue, diaphoresis, heat intolerance, tremors, palpitations, tachycardia, weight loss, hyperreflexia, and warm and moist skin. In women, menstrual abnormalities may be seen. In patients in whom the thyrotoxicosis is due to Graves’ disease, specific clinical manifestations may also include thyroid eye disease (ie, exophthalmos, lid lag), a diffuse goiter with a bruit, localized dermopathy, thyroid acropachy (ie, digital clubbing and swelling), and the coexistence of other autoimmune diseases in the patient or the patient’s family.
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 5
Thyroid Storm
Author Manuscript
Thyroid storm is the clinical manifestation of elevated serum thyroid hormone concentrations, resulting in the extreme alteration of usual hyperthyroid symptoms. The diagnosis can occur in patients with or without preexisting hyperthyroidism. It is a rare diagnosis and usually triggered by precipitants such as trauma, myocardial infarction, surgery (including thyroid surgery for hyperthyroidism or other surgeries in general), or infection. In some cases, acute exposure to excess iodine (ie, administration of iodinated contrast radiographic scan) may result in iodine-induced hyperthyroidism to trigger thyroid storm.23 Patients with known severe hyperthyroidism who are noncompliant with prescribed antithyroid medications may also develop thyroid storm.
Author Manuscript
Prompt recognition of thyroid storm is essential to initiate treatment, which should be performed in an ICU setting. Clinical manifestations of thyroid storm can be quite varied and may include fever, cardiac arrhythmias, vomiting, and impaired mental status. Patients with thyroid storm have increased inpatient mortality rate, overall hospital and ICU length of stay, and ventilation requirements compared with those with compensated thyrotoxicosis.24 The mortality rate of thyroid storm ranges from 10% to 20%.25, 26
Author Manuscript
Diagnosis of thyroid storm is made using a combination of biochemical laboratory tests confirming thyrotoxicosis in a patient displaying the severe, life-threatening symptoms of hyperthyroidism. Several diagnostic scoring systems have been proposed that can be used to assess the likelihood of thyroid storm in patients. The Burch-Wartofsky scoring system is based on factors related to temperature, central nervous system effects, gastrointestinal/ hepatic dysfunction, cardiovascular dysfunction, heart failure, and any precipitant history.27 The Akamizu criteria are similar and have also been proposed as another diagnostic scoring system in the assessment of thyroid storm.28 Treatment usually consists of multiple measures and medications aimed to target the various causes and effects of thyrotoxicosis, as summarized in Table 4.19, 22 Symptomatic improvement of tachycardia and clinical manifestations reflecting the increased adrenergic tone can be achieved with beta-blocker therapy. Methimazole or propylthiouracil should be initiated to decrease production of thyroid hormone. Saturated solution of potassium iodide can be used to inhibit thyroid hormone release from the thyroid gland. Glucocorticoids decrease the conversion of T4 to T3, which can also be accomplished by the use of propylthiouracil.29 Supportive measures include IV fluids, oxygen, cooling, and treatment of any precipitating causes. Finally, if necessary when the above treatments cannot be used or are unsuccessful, plasmapheresis can be attempted to decrease thyroid hormone excess, as well as cytokines and putative antibodies, in the circulation.30
Author Manuscript
CONCLUSION Hypothyroidism and thyrotoxicosis are common endocrine disorders, each with a variety of etiologies, and most patients with thyroid dysfunction are easily managed. However, in certain patients, severe, life-threatening forms of these states, representing rare thyroid emergencies, can develop on exposure to precipitating triggers or among patients with preexisting thyroid dysfunction or noncompliance with medical treatment. Both myxedema
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 6
Author Manuscript
coma, corresponding to extremely low serum thyroid hormone concentrations, and thyroid storm, corresponding to extremely elevated thyroid hormone concentrations, are associated with increased mortality and must be recognized promptly. Treatment of myxedema coma and thyroid storm is multifaceted and should be managed by the interdisciplinary team of an ICU setting.
Acknowledgments The author received funding from the National Institutes of Health, NIH 7K23HD068552.
References
Author Manuscript Author Manuscript Author Manuscript
1. Fekete C, Lechan RM. Central regulation of hypothalamic-pituitary-thyroid axis under physiological and pathophysiological conditions. Endocr Rev. 2014; 35(2):159–194. [PubMed: 24423980] 2. Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol. 2015; 3(4):286–295. [PubMed: 25591468] 3. Brent GA. Mechanisms of thyroid hormone action. J Clin Invest. 2012; 122(9):3035–3043. [PubMed: 22945636] 4. Gereben B, Zavacki AM, Ribich S, et al. Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling. Endocr Rev. 2008; 29(7):898–938. [PubMed: 18815314] 5. Hollowell JG, Staehling NW, Flanders WD, et al. Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab. 2002; 87(2):489–499. [PubMed: 11836274] 6. Canaris GJ, Manowitz NR, Mayor G, Ridgway EC. The Colorado thyroid disease prevalence study. Arch Intern Med. 2000; 160(4):526–534. [PubMed: 10695693] 7. Leung AM, Braverman LE. Consequences of excess iodine. Nat Rev Endocrinol. 2014; 10(3):136– 142. [PubMed: 24342882] 8. Zoeller RT, Rovet J. Timing of thyroid hormone action in the developing brain: clinical observations and experimental findings. J Neuroendocrinol. 2004; 16(10):809–818. [PubMed: 15500540] 9. Lazarus JH. Thyroid disorders associated with pregnancy: etiology, diagnosis, and management. Treat Endocrinol. 2005; 4(1):31–41. [PubMed: 15649099] 10. Haddow JE, Palomaki GE, Allan WC, et al. Maternal thyroid deficiency during pregnancy and subsequent neuropsychological development of the child. N Engl J Med. 1999; 341(8):549–555. [PubMed: 10451459] 11. Pop VJ, Kuijpens JL, van Baar AL, et al. Low maternal free thyroxine concentrations during early pregnancy are associated with impaired psychomotor development in infancy. Clin Endocrinol (Oxf). 1999; 50(2):149–155. [PubMed: 10396355] 12. Pop VJ, Brouwers EP, Vader HL, Vulsma T, van Baar AL, de Vijlder JJ. Maternal hypothyroxinaemia during early pregnancy and subsequent child development: a 3-year follow-up study. Clin Endocrinol (Oxf). 2003; 59(3):282–288. [PubMed: 12919150] 13. Wheeler SM, Willoughby KA, McAndrews MP, Rovet JF. Hippocampal size and memory functioning in children and adolescents with congenital hypothyroidism. J Clin Endocrinol Metab. 2011; 96(9):E1427–E1434. [PubMed: 21697249] 14. Samadi A, Skocic J, Rovet JF. Children born to women treated for hypothyroidism during pregnancy show abnormal corpus callosum development. Thyroid. 2015; 25(5):494–502. [PubMed: 25780811] 15. Rovet, JF., Skocic, J., Khan, S. Grey matter reductions in children with congenital hypothyroidism: a voxel-based morphometry (VBM) neuroimaging study. Paper presented at: 14th International Thyroid Congress; September 11–16, 2010; Paris, France. 16. Wartofsky, L. Myxedema coma. In: Braverman, LE., Cooper, DS., editors. Werner & Ingbar’s the Thyroid: A Fundamental and Clinical Text. 10. Philadelphia, PA: Lippincott Williams & Wilkins; 2012. p. 600-605.
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 7
Author Manuscript Author Manuscript Author Manuscript
17. Popoveniuc G, Chandra T, Sud A, et al. A diagnostic scoring system for myxedema coma. Endocr Pract. 2014; 20(8):808–817. [PubMed: 24518183] 18. Mathew V, Misgar RA, Ghosh S, et al. Myxedema coma: a new look into an old crisis. J Thyroid Res. 2011; 2011:493462. [PubMed: 21941682] 19. Hampton J. Thyroid gland disorder emergencies: thyroid storm and myxedema coma. AACN Adv Crit Care. 2013; 24(3):325–332. [PubMed: 23880755] 20. Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the treatment of hypothyroidism: prepared by the American Thyroid Association task force on thyroid hormone replacement. Thyroid. 2014; 24(12):1670–1751. [PubMed: 25266247] 21. Golombek SG, Alpan G, Frey M, Corbi D, Lagamma EF. Stability of thyroid hormones during continuous infusion. J Perinat Med. 2011; 39(4):471–475. [PubMed: 21501101] 22. Bahn RS, Burch HB, Cooper DS, et al. Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocr Pract. 2011; 17(3):456–520. [PubMed: 21700562] 23. Alkhuja S, Pyram R, Odeyemi O. In the eye of the storm: iodinated contrast medium induced thyroid storm presenting as cardiopulmonary arrest. Heart Lung. 2013; 42(4):267–269. [PubMed: 23711892] 24. Angell TE, Lechner MG, Nguyen CT, Salvato VL, Nicoloff JT, LoPresti JS. Clinical features and hospital outcomes in thyroid storm: a retrospective cohort study. J Clin Endocrinol Metab. 2015; 100(2):451–459. [PubMed: 25343237] 25. Chiha M, Samarasinghe S, Kabaker AS. Thyroid storm: an updated review. J Intensive Care Med. 2015; 30(3):131–140. [PubMed: 23920160] 26. Karger S, Führer D. Thyroid storm—thyrotoxic crisis: an update [in German]. Dtsch Med Wochenschr. 2008; 133(10):479–484. [PubMed: 18302101] 27. Burch HB, Wartofsky L. Life-threatening thyrotoxicosis. Thyroid storm. Endocrinol Metab Clin North Am. 1993; 22(2):263–277. [PubMed: 8325286] 28. Akamizu T, Satoh T, Isozaki O. Diagnostic criteria, clinical features, and incidence of thyroid storm based on nationwide surveys. Thyroid. 2012; 22(7):661–679. [PubMed: 22690898] 29. Geffner DL, Azukizawa M, Hershman JM. Propylthiouracil blocks extrathyroidal conversion of thyroxine to triiodothyronine and augments thyrotropin secretion in man. J Clin Invest. 1975; 55(2):224–229. [PubMed: 805160] 30. Muller C, Perrin P, Faller B, Richter S, Chantrel F. Role of plasma exchange in the thyroid storm. Ther Apher Dial. 2011; 15(6):522–531. [PubMed: 22107688]
Author Manuscript J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 8
TABLE 1
Author Manuscript
Signs and Symptoms of Hypothyroidism General Fatigue Lethargy Weight gain Sleepiness Cold intolerance Skin and hair Dry, thick skin Coarse hair Eyebrow thinning
Author Manuscript
Brittle nails Decreased perspiration Cardiovascular system Bradycardia Elevation of blood pressure Hyperlipidemia Respiratory system Shortness of breath Hoarse voice Sleep apnea Gastrointestinal system
Author Manuscript
Constipation Decreased appetite Reproductive system Menstrual cycle irregularities Infertility Musculoskeletal system Arthralgia Neurological system Paresthesia Depression Mental impairment Slow movements
Author Manuscript
Hyporeflexia
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 9
TABLE 2
Author Manuscript
Management of Myxedema Coma Thyroid hormone replacement Levothyroxine (T4) Loading dose of 200–400 µg IV once Maintenance dose of 1.6 µg/kg/d IV/PO Liothyronine (T3) Loading dose of 5–20 µg IV/NG once Maintenance dose of 2.5–10 every 8 hours IV/PO Supportive measures IV fluids containing electrolytes and glucose Passive rewarming with a blanket
Author Manuscript
Treatment of any underlying comorbidities, including infection Glucocorticoids Hydrocortisone 100 mg IV every 8 hours if adrenal insufficiency is suspected Abbreviations: IV, intravenous; NG, nasogastric; PO, per oral.
Author Manuscript Author Manuscript J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 10
TABLE 3
Author Manuscript
Signs and Symptoms of Thyrotoxicosis General Fatigue Weight loss Insomnia Heat intolerance Eyes Exophthalmos, lid lag, or periorbital/conjunctival edema, if thyrotoxicosis is due to Graves’ disease Skin and hair Warm, moist skin Thin, fine hair
Author Manuscript
Brittle nails Diaphoresis Thyroid acropachy if due to Graves’ disease Localized dermopathy, if due to Graves’ disease Cardiovascular system Tachycardia Palpitations Atrial arrhythmias Systolic hypertension Hyperdynamic precordium Respiratory system
Author Manuscript
Shortness of breath Gastrointestinal system Loose stools or hyperdefecation Increased appetite Reproductive system Menstrual cycle irregularities Infertility Musculoskeletal system Muscle weakness, especially of proximal muscles Neurological system Nervousness Anxiety
Author Manuscript
Tremor Hyperactivity Hyperreflexia
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 11
TABLE 4
Author Manuscript
Management of Thyroid Storm Antithyroidal drugs Propylthiouracil Loading dose of 600 mg PO/NG/PR once Maintenance dose of 200–300 mg every 6 hours PO/NG/PR Methimazole Loading dose of 20 mg PO every 6 hours Saturated solution of potassium iodide 5 drops PO every 6 hours; must be started after antithyroid drug therapy is initiated to avoid potential worsening of hyperthyroidism Glucocorticoids Hydrocortisone 100 mg IV every 8 hours
Author Manuscript
Beta-blocker therapy Propranolol 40–80 mg PO every 4 hours or 2 mg IV every 4 hours Supportive measures IV fluids Oxygen Cooling Treatment of any precipitating causes Abbreviations: IV, intravenous; NG, nasogastric; PO, per oral; PR, per rectum.
Author Manuscript Author Manuscript J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
J Infus Nurs. Author manuscript; available in PMC 2017 October 26. Published in final edited form as: J Infus Nurs. 2016 ; 39(5): 281–286. doi:10.1097/NAN.0000000000000186.
Thyroid Emergencies Angela M Leung, MD, MSc Division of Endocrinology, David Geffen School of Medicine at UCLA, and the VA Greater Los Angeles Healthcare System, Los Angeles, California.
Abstract Author Manuscript
Myxedema coma and thyroid storm are thyroid emergencies associated with increased mortality. Prompt recognition of these states—which represent the severe, life-threatening conditions of extremely reduced or elevated circulating thyroid hormone concentrations, respectively—is necessary to initiate treatment. Management of myxedema coma and thyroid storm requires both medical and supportive therapies and should be treated in an intensive care unit setting.
Keywords hypothyroidism; hyperthyroidism; ICU; myxedema coma; thyroid emergencies; thyroid storm
Author Manuscript
The thyroid is a 15- to 20-gram gland located in the anterior neck. It is responsible for the production of the thyroid hormones T4 (thyroxine) and T3 (triiodothyronine). Various factors can affect thyroid hormone synthesis, including acute illness, coexisting morbidities, and certain medications. Both the states of low thyroid hormone concentrations (hypothyroidism) and thyroid hormone excess thyrotoxicosis) can be transient or permanent. The decompensated, severe forms of hypothyroidism and hyperthyroidism, termed myxedema coma and thyroid storm, are associated with increased morbidity and mortality. Prompt recognition of both conditions is necessary to initiate treatment and supportive measures. This review will summarize the essential principles of the clinical manifestations, diagnostic methods, and treatments of hypothyroidism and hyperthyroidism, both in the nonacute and life-threatening forms of these diseases.
THYROID HORMONE PRODUCTION AND METABOLISM Author Manuscript
The normal physiology of the hypothalamic-pituitary-thyroid axis involves the production of T4 and T3 by the thyroid gland, a process that is regulated by thyroid-stimulating hormone (TSH) secreted by the pituitary, which is, in turn, regulated by thyrotropin-releasing hormone (TRH) secreted by the hypothalamus. Both serum T4 and T3 concentrations act as negative feedback regulators of TSH and TRH secretion, but can be altered by
Corresponding Author: Angela M. Leung, MD, MSc, VA Greater Los Angeles Healthcare Sysem, Divison of Endocrinology (111D), 11301 Wilshire Blvd, Los Angeles, CA 90073 ([email protected]). Angela M. Leung, MD, MSc, is an assistant clinical professor of medicine in the Division of Endocrinology at the David Geffen School of Medicine at the University of California, Los Angeles, and the VA Greater Los Angeles Healthcare System, both in Los Angeles, California. The author has no other potential conflicts of interest to disclose.
Leung
Page 2
Author Manuscript
environmental conditions—including food availability and temperature—and disease states, such as infection.1 Thyroid hormone synthesis is achieved first through active transport of circulating iodide, which is taken in from the diet, by the sodium/iodide symporter located at the basolateral membrane of the thyroid follicular cell.2 Iodide then becomes oxidized by thyroid peroxidase (TPO) and hydrogen peroxide at the apical membrane, which then attaches to the tyrosyl residues on thyroglobulin (Tg) to produce monoiodotyrosine (MIT) and diiodotyrosine (DIT). MIT and DIT are the precursors to the thyroid hormones, which are produced by the linkage of 2 DIT molecules to form T4 and the linkage of MIT and DIT to produce T3. Release of T4 and T3 into the circulation results from the digestion of Tg in MIT and DIT by endosomal and lysosomal proteases.
Author Manuscript
The metabolic effects of thyroid hormone action result from the binding of the thyroid hormone to thyroid hormone transporters located in specific target tissues, which is mediated by the thyroid hormone nuclear receptor (TR) that is encoded by the genes TRα and TRβ.3 While the sole source of T4 is the thyroid gland, the majority (approximately 80%) of T3 is produced from the extrathyroidal conversion of T4 to T3 by the action of the 5 ´-deiodinase enzymes—D1 or D2—located in the liver, brain, brown adipose tissue, and muscles.4 T4 can also be converted to the inactive thyroid hormones, reverse T3 or T2, by the 5´-deiodinase D3. The activity and expression of the deiodinases are specific to different tissues and environmental conditions.
SERUM THYROID FUNCTION AND ANTIBODIES Author Manuscript
Serum TSH is the most sensitive test to suggest thyroid dysfunction, because of the logarithmic-linear relationship between serum TSH and thyroid hormone levels. Overt thyroid dysfunction, whether referring to hypothyroidism or hyperthyroidism, is defined by the sole abnormality of an elevated serum TSH concentration, while subclinical thyroid dysfunction refers to both elevated serum TSH and decreased T3 and/or T4 concentrations. The range of subclinical to overt thyroid dysfunction can be regarded as a continuum of increasingly severe biochemical thyroid disease, which incidentally may or may not correlate to the severity of any corresponding symptoms, if present.
HYPOTHYROIDISM
Author Manuscript
Hypothyroidism refers to the state of low circulating thyroid hormones. In 2 large US population-based studies of data collected in the 1980s to the 1990s, the prevalence of overt hypothyroidism ranged from 0.3% to 0.4%, while that of subclinical hypothyroidism ranged from 4.3% to 8.5%, among the general population.5, 6 The most common etiology of hypothyroidism in the United States is Hashimoto’s thyroiditis, an autoimmune disease that is more prevalent among older women; nutritional iodine deficiency is the most common etiology worldwide. Additional etiologies of hypothyroidism include a history of thyroidectomy, radioactive iodine therapy, and, less commonly, decreased TSH production by the pituitary. Predisposition factors for the development of hypothyroidism include thyroid autoimmunity (which can be assessed by the determination of serum thyroid
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 3
Author Manuscript
autoantibodies, such as TPO and [Tg] antibody titers), the use of certain medications (ie, lithium, amiodarone, interferon-alpha), and excess iodine exposure (ie, from iodinated contrast radiographic studies), in which individuals with a history of thyroid disease are at higher risk of iodine-induced hypothyroidism.7 Thyroid hormone is important for the metabolic functions of many major organs, including the heart, brain, liver, and muscle. Signs and symptoms of hypothyroidism are widely variable (Table 1), often subtle, and may include fatigue, malaise, weight gain, dry and puffy skin, constipation, cold intolerance, altered cognition, and hyporeflexia. In children, there may be stunted growth, and in women, menstrual abnormalities may be present. Hypothyroidism Among Women of Reproductive Age and in Children
Author Manuscript
Normal thyroid function is particularly important among pregnant and lactating women, the developing fetus, and young children. As thyroid hormone is crucial for the complex processes of neurodevelopment and growth,8 which begins in the first trimester of pregnancy and continues into the first few years of infancy, these groups are especially susceptible to the effects of even mild thyroid dysfunction. Several studies have demonstrated that low thyroid hormone levels among pregnant women are associated with increased risks of preterm delivery, spontaneous miscarriage, fetal death, and cognitive deficits,9 including a decrement in intelligence quotient and memory scores of the offspring, compared with euthyroid women.10–13 Neuroimaging studies also show abnormalities of hippocampal and corpus callosum size, and of gray matter, among children with a form of low thyroid hormone levels at birth termed congenital hypothyroidism.14, 15 Myxedema Coma
Author Manuscript
Myxedema coma refers to the state of severe, life-threatening, and decompensated hypothyroidism in which thyroid hormone levels are dangerously low. The diagnosis appears to be more common in elderly women with long-standing preexisting hypothyroidism. Triggers may include cold temperature (thus, it is more common during winter months); precipitating comorbidities, such as infection, stroke, and heart failure; or the use of sedative, analgesic, antidepressant, hypnotic, antipsychotic, or anesthetic medications.16 Patients with preexisting hypothyroidism may also present with myxedema coma following a period of prolonged noncompliance with thyroid hormone replacement.
Author Manuscript
Signs and symptoms usually are exacerbations of the usual manifestations of hypothyroidism and may include extreme lethargy, which can progress to stupor or coma, hypothermia, respiratory depression, bradycardia, hyponatremia, and renal impairment. The diagnosis of myxedema coma is made with the confirmation of a biochemical thyroid profile consistent with hypothyroidism and corresponding clinical manifestations. A diagnostic scoring system has been proposed to guide the clinician toward a diagnosis of myxedema coma based on body temperature, central nervous system signs, gastrointestinal symptoms, precipitating events, cardiovascular dysfunction, and metabolic disturbances.17 Treatment of myxedema coma should be considered as quickly as possible, given the increased mortality of the disease (25%–60% despite treatment),18 and can be started even before confirmation of laboratory results demonstrating abnormal serum TSH and T4 J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 4
Author Manuscript
concentrations. The management of myxedema coma should be in an intensive care unit (ICU) setting. The central tenets of treatment are thyroid hormone replacement, stress-dose corticosteroids if concomitant adrenal insufficiency is suspected, supportive care, and the treatment of any underlying and coexisting conditions (Table 2). Supportive care may include the administration of intravenous (IV) fluids, sodium replacement if hyponatremia is present, and the use of warming blankets (although aggressive rewarming should be avoided, given the risks of vasodilation).19
Author Manuscript
Thyroid hormone replacement should be administered as T4 and/or T3, often intravenously, given the impaired state of the patient. Suggested regimens for the initial and maintenance doses of thyroid hormone in a patient with myxedema coma are provided in Table 2. In general, a loading dose of 200 to 400 µg IV levothyroxine (T4) is to be followed by a maintenance dose of 1.6 µg/kg/d when given orally or 75% of this when given intravenously; consideration can also be made for the coadministration of liothyronine (T3), since T4 to T3 conversion may be impaired in patients with myxedema coma.20 It is important to note that IV thyroid hormone replacement should be administered only as a push through a syringe, rather than through infusion tubing, in which up to 40% of the starting concentration may be lost from adherence to polypropylene tubing.21 Improvements in serum T3 and T4 concentrations may be seen before the normalization of serum TSH concentrations, and measurement of serum thyroid function tests every 1 to 2 days during treatment is reasonable.20 Improvements in clinical cardiovascular, renal, pulmonary, and metabolic parameters may take as much as a week to be observed.20
THYROTOXICOSIS Author Manuscript
Thyrotoxicosis refers to the state of thyroid hormone excess arising from either overproduction from the thyroid gland (termed hyperthyroidism) or extrathyroidal, including exogenous, sources. Of the etiologies attributable to hyperthyroidism, the most common cause worldwide is Graves’ disease, resulting from the autoimmune stimulation of the thyroid by serum thyroid-stimulating immunoglobulin, followed by toxic multinodular goiter and toxic adenoma. In the United States, the prevalence of hyperthyroidism from all causes is approximately 1.2%, of which 0.5% is overt and 0.7% is subclinical.22 Other causes of thyrotoxicosis include overproduction of TSH from a pituitary adenoma, thyroiditis, exogenous thyroid hormone ingestion, ectopic hyperthyroidism (such as from struma ovarii or metastatic thyroid cancer), or human chorionic gonadotropin-mediated hyperthyroidism (such as from hyperemesis gravidarum or a molar pregnancy).
Author Manuscript
The signs and symptoms of thyrotoxicosis are reflective of the excess concentrations of thyroid hormone present (Table 3) and can include anxiety, fatigue, diaphoresis, heat intolerance, tremors, palpitations, tachycardia, weight loss, hyperreflexia, and warm and moist skin. In women, menstrual abnormalities may be seen. In patients in whom the thyrotoxicosis is due to Graves’ disease, specific clinical manifestations may also include thyroid eye disease (ie, exophthalmos, lid lag), a diffuse goiter with a bruit, localized dermopathy, thyroid acropachy (ie, digital clubbing and swelling), and the coexistence of other autoimmune diseases in the patient or the patient’s family.
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 5
Thyroid Storm
Author Manuscript
Thyroid storm is the clinical manifestation of elevated serum thyroid hormone concentrations, resulting in the extreme alteration of usual hyperthyroid symptoms. The diagnosis can occur in patients with or without preexisting hyperthyroidism. It is a rare diagnosis and usually triggered by precipitants such as trauma, myocardial infarction, surgery (including thyroid surgery for hyperthyroidism or other surgeries in general), or infection. In some cases, acute exposure to excess iodine (ie, administration of iodinated contrast radiographic scan) may result in iodine-induced hyperthyroidism to trigger thyroid storm.23 Patients with known severe hyperthyroidism who are noncompliant with prescribed antithyroid medications may also develop thyroid storm.
Author Manuscript
Prompt recognition of thyroid storm is essential to initiate treatment, which should be performed in an ICU setting. Clinical manifestations of thyroid storm can be quite varied and may include fever, cardiac arrhythmias, vomiting, and impaired mental status. Patients with thyroid storm have increased inpatient mortality rate, overall hospital and ICU length of stay, and ventilation requirements compared with those with compensated thyrotoxicosis.24 The mortality rate of thyroid storm ranges from 10% to 20%.25, 26
Author Manuscript
Diagnosis of thyroid storm is made using a combination of biochemical laboratory tests confirming thyrotoxicosis in a patient displaying the severe, life-threatening symptoms of hyperthyroidism. Several diagnostic scoring systems have been proposed that can be used to assess the likelihood of thyroid storm in patients. The Burch-Wartofsky scoring system is based on factors related to temperature, central nervous system effects, gastrointestinal/ hepatic dysfunction, cardiovascular dysfunction, heart failure, and any precipitant history.27 The Akamizu criteria are similar and have also been proposed as another diagnostic scoring system in the assessment of thyroid storm.28 Treatment usually consists of multiple measures and medications aimed to target the various causes and effects of thyrotoxicosis, as summarized in Table 4.19, 22 Symptomatic improvement of tachycardia and clinical manifestations reflecting the increased adrenergic tone can be achieved with beta-blocker therapy. Methimazole or propylthiouracil should be initiated to decrease production of thyroid hormone. Saturated solution of potassium iodide can be used to inhibit thyroid hormone release from the thyroid gland. Glucocorticoids decrease the conversion of T4 to T3, which can also be accomplished by the use of propylthiouracil.29 Supportive measures include IV fluids, oxygen, cooling, and treatment of any precipitating causes. Finally, if necessary when the above treatments cannot be used or are unsuccessful, plasmapheresis can be attempted to decrease thyroid hormone excess, as well as cytokines and putative antibodies, in the circulation.30
Author Manuscript
CONCLUSION Hypothyroidism and thyrotoxicosis are common endocrine disorders, each with a variety of etiologies, and most patients with thyroid dysfunction are easily managed. However, in certain patients, severe, life-threatening forms of these states, representing rare thyroid emergencies, can develop on exposure to precipitating triggers or among patients with preexisting thyroid dysfunction or noncompliance with medical treatment. Both myxedema
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 6
Author Manuscript
coma, corresponding to extremely low serum thyroid hormone concentrations, and thyroid storm, corresponding to extremely elevated thyroid hormone concentrations, are associated with increased mortality and must be recognized promptly. Treatment of myxedema coma and thyroid storm is multifaceted and should be managed by the interdisciplinary team of an ICU setting.
Acknowledgments The author received funding from the National Institutes of Health, NIH 7K23HD068552.
References
Author Manuscript Author Manuscript Author Manuscript
1. Fekete C, Lechan RM. Central regulation of hypothalamic-pituitary-thyroid axis under physiological and pathophysiological conditions. Endocr Rev. 2014; 35(2):159–194. [PubMed: 24423980] 2. Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol. 2015; 3(4):286–295. [PubMed: 25591468] 3. Brent GA. Mechanisms of thyroid hormone action. J Clin Invest. 2012; 122(9):3035–3043. [PubMed: 22945636] 4. Gereben B, Zavacki AM, Ribich S, et al. Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling. Endocr Rev. 2008; 29(7):898–938. [PubMed: 18815314] 5. Hollowell JG, Staehling NW, Flanders WD, et al. Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab. 2002; 87(2):489–499. [PubMed: 11836274] 6. Canaris GJ, Manowitz NR, Mayor G, Ridgway EC. The Colorado thyroid disease prevalence study. Arch Intern Med. 2000; 160(4):526–534. [PubMed: 10695693] 7. Leung AM, Braverman LE. Consequences of excess iodine. Nat Rev Endocrinol. 2014; 10(3):136– 142. [PubMed: 24342882] 8. Zoeller RT, Rovet J. Timing of thyroid hormone action in the developing brain: clinical observations and experimental findings. J Neuroendocrinol. 2004; 16(10):809–818. [PubMed: 15500540] 9. Lazarus JH. Thyroid disorders associated with pregnancy: etiology, diagnosis, and management. Treat Endocrinol. 2005; 4(1):31–41. [PubMed: 15649099] 10. Haddow JE, Palomaki GE, Allan WC, et al. Maternal thyroid deficiency during pregnancy and subsequent neuropsychological development of the child. N Engl J Med. 1999; 341(8):549–555. [PubMed: 10451459] 11. Pop VJ, Kuijpens JL, van Baar AL, et al. Low maternal free thyroxine concentrations during early pregnancy are associated with impaired psychomotor development in infancy. Clin Endocrinol (Oxf). 1999; 50(2):149–155. [PubMed: 10396355] 12. Pop VJ, Brouwers EP, Vader HL, Vulsma T, van Baar AL, de Vijlder JJ. Maternal hypothyroxinaemia during early pregnancy and subsequent child development: a 3-year follow-up study. Clin Endocrinol (Oxf). 2003; 59(3):282–288. [PubMed: 12919150] 13. Wheeler SM, Willoughby KA, McAndrews MP, Rovet JF. Hippocampal size and memory functioning in children and adolescents with congenital hypothyroidism. J Clin Endocrinol Metab. 2011; 96(9):E1427–E1434. [PubMed: 21697249] 14. Samadi A, Skocic J, Rovet JF. Children born to women treated for hypothyroidism during pregnancy show abnormal corpus callosum development. Thyroid. 2015; 25(5):494–502. [PubMed: 25780811] 15. Rovet, JF., Skocic, J., Khan, S. Grey matter reductions in children with congenital hypothyroidism: a voxel-based morphometry (VBM) neuroimaging study. Paper presented at: 14th International Thyroid Congress; September 11–16, 2010; Paris, France. 16. Wartofsky, L. Myxedema coma. In: Braverman, LE., Cooper, DS., editors. Werner & Ingbar’s the Thyroid: A Fundamental and Clinical Text. 10. Philadelphia, PA: Lippincott Williams & Wilkins; 2012. p. 600-605.
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 7
Author Manuscript Author Manuscript Author Manuscript
17. Popoveniuc G, Chandra T, Sud A, et al. A diagnostic scoring system for myxedema coma. Endocr Pract. 2014; 20(8):808–817. [PubMed: 24518183] 18. Mathew V, Misgar RA, Ghosh S, et al. Myxedema coma: a new look into an old crisis. J Thyroid Res. 2011; 2011:493462. [PubMed: 21941682] 19. Hampton J. Thyroid gland disorder emergencies: thyroid storm and myxedema coma. AACN Adv Crit Care. 2013; 24(3):325–332. [PubMed: 23880755] 20. Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the treatment of hypothyroidism: prepared by the American Thyroid Association task force on thyroid hormone replacement. Thyroid. 2014; 24(12):1670–1751. [PubMed: 25266247] 21. Golombek SG, Alpan G, Frey M, Corbi D, Lagamma EF. Stability of thyroid hormones during continuous infusion. J Perinat Med. 2011; 39(4):471–475. [PubMed: 21501101] 22. Bahn RS, Burch HB, Cooper DS, et al. Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocr Pract. 2011; 17(3):456–520. [PubMed: 21700562] 23. Alkhuja S, Pyram R, Odeyemi O. In the eye of the storm: iodinated contrast medium induced thyroid storm presenting as cardiopulmonary arrest. Heart Lung. 2013; 42(4):267–269. [PubMed: 23711892] 24. Angell TE, Lechner MG, Nguyen CT, Salvato VL, Nicoloff JT, LoPresti JS. Clinical features and hospital outcomes in thyroid storm: a retrospective cohort study. J Clin Endocrinol Metab. 2015; 100(2):451–459. [PubMed: 25343237] 25. Chiha M, Samarasinghe S, Kabaker AS. Thyroid storm: an updated review. J Intensive Care Med. 2015; 30(3):131–140. [PubMed: 23920160] 26. Karger S, Führer D. Thyroid storm—thyrotoxic crisis: an update [in German]. Dtsch Med Wochenschr. 2008; 133(10):479–484. [PubMed: 18302101] 27. Burch HB, Wartofsky L. Life-threatening thyrotoxicosis. Thyroid storm. Endocrinol Metab Clin North Am. 1993; 22(2):263–277. [PubMed: 8325286] 28. Akamizu T, Satoh T, Isozaki O. Diagnostic criteria, clinical features, and incidence of thyroid storm based on nationwide surveys. Thyroid. 2012; 22(7):661–679. [PubMed: 22690898] 29. Geffner DL, Azukizawa M, Hershman JM. Propylthiouracil blocks extrathyroidal conversion of thyroxine to triiodothyronine and augments thyrotropin secretion in man. J Clin Invest. 1975; 55(2):224–229. [PubMed: 805160] 30. Muller C, Perrin P, Faller B, Richter S, Chantrel F. Role of plasma exchange in the thyroid storm. Ther Apher Dial. 2011; 15(6):522–531. [PubMed: 22107688]
Author Manuscript J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 8
TABLE 1
Author Manuscript
Signs and Symptoms of Hypothyroidism General Fatigue Lethargy Weight gain Sleepiness Cold intolerance Skin and hair Dry, thick skin Coarse hair Eyebrow thinning
Author Manuscript
Brittle nails Decreased perspiration Cardiovascular system Bradycardia Elevation of blood pressure Hyperlipidemia Respiratory system Shortness of breath Hoarse voice Sleep apnea Gastrointestinal system
Author Manuscript
Constipation Decreased appetite Reproductive system Menstrual cycle irregularities Infertility Musculoskeletal system Arthralgia Neurological system Paresthesia Depression Mental impairment Slow movements
Author Manuscript
Hyporeflexia
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 9
TABLE 2
Author Manuscript
Management of Myxedema Coma Thyroid hormone replacement Levothyroxine (T4) Loading dose of 200–400 µg IV once Maintenance dose of 1.6 µg/kg/d IV/PO Liothyronine (T3) Loading dose of 5–20 µg IV/NG once Maintenance dose of 2.5–10 every 8 hours IV/PO Supportive measures IV fluids containing electrolytes and glucose Passive rewarming with a blanket
Author Manuscript
Treatment of any underlying comorbidities, including infection Glucocorticoids Hydrocortisone 100 mg IV every 8 hours if adrenal insufficiency is suspected Abbreviations: IV, intravenous; NG, nasogastric; PO, per oral.
Author Manuscript Author Manuscript J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 10
TABLE 3
Author Manuscript
Signs and Symptoms of Thyrotoxicosis General Fatigue Weight loss Insomnia Heat intolerance Eyes Exophthalmos, lid lag, or periorbital/conjunctival edema, if thyrotoxicosis is due to Graves’ disease Skin and hair Warm, moist skin Thin, fine hair
Author Manuscript
Brittle nails Diaphoresis Thyroid acropachy if due to Graves’ disease Localized dermopathy, if due to Graves’ disease Cardiovascular system Tachycardia Palpitations Atrial arrhythmias Systolic hypertension Hyperdynamic precordium Respiratory system
Author Manuscript
Shortness of breath Gastrointestinal system Loose stools or hyperdefecation Increased appetite Reproductive system Menstrual cycle irregularities Infertility Musculoskeletal system Muscle weakness, especially of proximal muscles Neurological system Nervousness Anxiety
Author Manuscript
Tremor Hyperactivity Hyperreflexia
J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
Leung
Page 11
TABLE 4
Author Manuscript
Management of Thyroid Storm Antithyroidal drugs Propylthiouracil Loading dose of 600 mg PO/NG/PR once Maintenance dose of 200–300 mg every 6 hours PO/NG/PR Methimazole Loading dose of 20 mg PO every 6 hours Saturated solution of potassium iodide 5 drops PO every 6 hours; must be started after antithyroid drug therapy is initiated to avoid potential worsening of hyperthyroidism Glucocorticoids Hydrocortisone 100 mg IV every 8 hours
Author Manuscript
Beta-blocker therapy Propranolol 40–80 mg PO every 4 hours or 2 mg IV every 4 hours Supportive measures IV fluids Oxygen Cooling Treatment of any precipitating causes Abbreviations: IV, intravenous; NG, nasogastric; PO, per oral; PR, per rectum.
Author Manuscript Author Manuscript J Infus Nurs. Author manuscript; available in PMC 2017 October 26.
